Field of the Invention
The invention relates to audio/video systems, and, in particular, to a method for synchronizing video data and audio data in a virtual reality (VR) system including a VR device and a host device.
Description of the Related Art
Displays with virtual image generation are often used in display devices which are located close to the user's eyes. These are called near-to-eye displays. Such display devices are known, for example, as head mounted displays (HMD).
An HMD is a display device that a person wears on the head in order to have video information directly displayed in front of the eyes. An HMD has either one or two small CRT, LCD or OLED displays with magnifying lenses and other optical elements. The displays and optics are typically embedded in a helmet, glasses, or a visor, which the user can wear. Lenses and other optical components are used to give the user the perception that the images are coming from a greater distance, and to prevent eyestrain.
The display video data, images, or frames are generated and output by a host device. When the host device transmits the video data and associated audio data to a VR device, non-synchronization (or audio drift) between the audio data and video data may occur because the processing time in the audio transmission path may differ from that in the video transmission path. That is, the audio path delay and the video path delay can be different. Differing delays between the audio transmission path and the video transmission path can cause the audio portion of the content and the video portion of the content to become “out of sync” in time (i.e. the audio lagging behind the video, or with the video delayed with respect to the audio), and the time mismatch between the audio data and the video data can cause significant distraction and dissatisfaction to the viewer. Accordingly, there is demand for a method for synchronizing the video data and audio data in a virtual reality (VR) system including a VR device and a host device.